Recessed fan inlet cover

ABSTRACT

A recessed fan inlet cover, for covering an enclosure inlet opening of an exhaust fan enclosure to provide an air flow channel into the fan enclosure while impeding sound emission from the fan enclosure, the fan inlet cover comprising: a cover frame having an outer peripheral edge extending outward of the enclosure inlet opening and having an inner edge defining a substantially planar frame surface, the frame having an upwardly recessed mounting surface joined to the inner edge with an arcuate wall, the mounting surface having an intake opening; and a cover plug mounted to the recessed mounting surface downwardly spaced from the mounting surface, the plug having a substantially planar plug surface co-planar with said frame surface, the plug having an outer peripheral edge with an inwardly projecting lip, the plug having a sound absorbing layer on an upper surface opposite said planar plug surface; wherein an air flow channel is defined between said arcuate wall and said lip.

TECHNICAL FIELD

The invention relates to a recessed sound attenuating fan inlet coverwith a flush outer surface profile.

BACKGROUND OF THE ART

Exhaust fans are well known in the prior art, for example fans which areinstalled in ceilings of residential or commercial buildings to exhaustair from kitchens or bathrooms. In general, a sheet metal fan enclosurehouses a rotating blower wheel or fan driven by an electric motor. Theenclosure has an inlet opening to intake air into the fan which is thenexpelled from the enclosure through an outlet into an exhaust duct.

For visual effect, dust control, noise control and to define an inletairflow path, fan enclosures are usually fitted with a cover which canrange from a simple grill or grate to relatively complex covers whichattempt to produce less turbulent airflow and reduce propagation ofsound from the electric motor and fan blade themselves. Conventionalenclosures are usually of minimum size to house the fan and motor.Conventionally, the covers extend over the fan enclosure opening andextend outwardly past a surface of the wall or ceiling into which theyare mounted. Conventional covers intake air laterally reducing theperception of airflow turbulence directly below or in front of a fancover.

It is desirable to provide a fan enclosure cover that provides lessturbulent airflow reducing noise generated by airflow and friction, thatreduces propagation of vibrations and sound from the electric motor andfan blades, that is aesthetically pleasing and that reduces the visualimpact of the fan cover as much possible.

Features that distinguish the present invention from the background artwill be apparent from review of the disclosure, drawings and descriptionof the invention presented below.

DISCLOSURE OF THE INVENTION

The invention provides a recessed fan inlet cover, for covering anenclosure inlet opening of an exhaust fan enclosure to provide an airflow channel into the fan enclosure while impeding sound emission fromthe fan enclosure, the fan inlet cover comprising: a cover frame havingan outer peripheral edge extending outward of the enclosure inletopening and having an inner edge defining a substantially planar framesurface, the frame having an upwardly recessed mounting surface joinedto the inner edge with an arcuate wall, the mounting surface having anintake opening; and a cover plug mounted to the recessed mountingsurface downwardly spaced from the mounting surface, the plug having asubstantially planar plug surface co-planar with said frame surface, theplug having an outer peripheral edge with an inwardly projecting lip,the plug having a sound absorbing layer on an upper surface oppositesaid planar plug surface; wherein an air flow channel is defined betweensaid arcuate wall and said lip.

DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood, one embodiment ofthe invention is illustrated by way of example in the accompanyingdrawings.

FIG. 1 shows a vertical section through a conventional prior art fanenclosure having a cover plate extending downwardly beyond a ceilingsurface and drawing air into the inlet of the fan or blower to beexpelled through the enclosure outlet and lateral exhaust duct.

FIG. 2 shows a bottom perspective view of a recessed fan inlet coveraccording to the invention.

FIG. 3 shows a plan view of the inlet cover according to the invention.

FIG. 4 shows a side view of the recessed fan inlet cover.

FIG. 5 shows a perspective view similar to FIG. 2 with the cover plugremoved to show the cover frame by itself.

FIG. 6 is a sectional view through the recessed fan inlet cover andthrough the exhaust enclosure.

FIG. 7 shows a sectional view similar to FIG. 4 illustrating the arcuatewall surface of the cover frame and the opposing inwardly projecting lipof the plug which defines the airflow channel into the fan enclosure.

Further details of the invention and its advantages will be apparentfrom the detailed description included below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a vertical sectional view through a prior art exhaust fanenclosure 1. The exhaust fan enclosure 1 is mounted to the ceiling 2 ina conventional manner known to those skilled in the art. The enclosure 1is generally of sheet metal having a inlet opening 3 covered by a faninlet cover 4. An electric motor 5 drives a rotating fan or blower 6 tointake air as indicated with arrows in FIG. 1 from a central intake andoutlet duct 7 from the enclosure. The electric motor 5 and airturbulence caused by the blower 6 creates sound which can be propagateddownwardly into the room from which the air is exhausted. The functionof the fan inlet cover 4 is to direct airflow into the central blowerinlet, to visually disguise the opening 3 to the fan enclosure 1 and toreduce the noise propagated into the room from the motor 5 and fan 6.

As indicated in FIG. 1, typically the cover 4 extends downwardly fromthe ceiling 2 into the room by dimension “d”. Designers may assume thatextending the cover 4 into the room is necessary to draw in airlaterally from a large area. However, extending into the room bydimension “d” disturbs the otherwise flush surface of a ceiling or walland disturb the aesthetic appeal of a room. For example, in a wellappointed washroom, the inexpensive plastic fan cover is generally theleast expensive and least attractive element in the room, compared tolight fixtures, plumbing fixtures, tiles, mirrors, and linens. However,to exhaust air, some type of fan cover is required.

In contrast, the present invention discloses in FIGS. 2-7 a novelrecessed fan inlet cover 8 that is also positioned over the enclosureinlet opening 3 of an exhaust fan enclosure 1. The fan inlet cover 8 isrecessed to provide a flush surface substantially planar across thesurface of the cover 8.

As seen in FIG. 6, the recessed cover 8 has a central portion which isrecessed into the enclosure inlet opening 3 to define a novel means ofproviding an air inflow channel 22 to reduce turbulence as well as tomount sound absorbing material in a central plug 17 of the cover 8 asdescribed below.

Further, a substantially planar lower surface 18 of the plug 17 andframe 9 of the cover 8 intrudes minimally into the room below theceiling 2 surface from which air is exhausted.

FIGS. 2, 3, and 4 show the outer surfaces of a recessed fan inlet cover8 for covering an enclosure inlet 3 of an exhaust fan enclosure 1 (seeFIG. 6). The recessed fan inlet cover 8 provides an airflow channel 22into the fan enclosure 1 while impeding sound emission from the fanenclosure 1.

As seen in FIGS. 2, 3 and 4 the fan inlet cover 8 includes a cover frame9 having an outer peripheral edge 10 that extends outward of theenclosure inlet opening 3. The cover frame 9 has an inner edge 11 thattogether with the outer edge 10 defines a substantially planar framesurface 12 therebetween.

As seen in FIGS. 5, 6 and 7, the frame 9 has an upwardly recessedmounting surface 13 joined to the inner edge 11 with an arcuate wall 14.The mounting surface 13 has an interior intake opening 15 through whichair drawn from the room enters into the fan intake. A sloping planarwall 16 optionally extends upwardly and inwardly from the inner edge 11to the arcuate wall 14.

Referring to FIGS. 2, 3 and 4, the recessed fan inlet cover 8 has acentrally positioned cover plug 17 mounted to the recessed mountingsurface 13 and downwardly spaced from the mounting surface 13 to definean airflow channel 22. The plug 17 has a substantially planar plugsurface 18 that is substantially co-planar with the frame surface 12,best seen in FIG. 4. In this manner, the recessed fan inlet cover 8intrudes a minimal amount into the ceiling area of the room from whichair is exhausted. The recessing of the air channel 22 and cover plug 17results in a minimal intrusion.

The cover plug 17 has an outer peripheral edge 19 for example seen inFIG. 7 with an inwardly projecting lip 20. To absorb and preventpropagation of sound from the electric motor 5 and fan blower 6, theplug 17 includes a sound absorbing layer 21 on an upper surface oppositeto the planar plug surface 18. The airflow channel 22 therefore isdefined between the arcuate wall 14 and the lip 20. As best seen in FIG.7, the lip 20 and sloping planar wall 16 can be in parallel orientationwith smooth rounded edges 19 and smooth transition to the arcuate wall14 to reduce airflow turbulence and smooth the intake of air flow.

Preferably, the airflow channel 22 has an overall intake area relativeto the enclosure inlet opening area in the range of 40 to 60% and mostpreferably in the range of 45 to 55%. Utilizing the cover plug 17 spacedfrom the recessed portion of the cover frame 8 to define the airflowchannel 22 enables a relatively large intake area for the airflowchannel 22 with visual masking of the blower 6 as indicated by line ofsight 23 in FIG. 7. The sound absorbing layer 21 combined with theorientation of the frame 9 and plug 17 prevents sound from escaping in adirect path thereby reducing the propagation of sound from the electricmotor 5 and fan 6.

The recessed space created between the plug 17 and frame 9, the spacecreated within the layer 21 and above the plug 17 can accommodate anelectric night light, motion sensors, humidity sensors, smoke detectorsand other wall/ceiling mounted devices. Since electric power andconductors must be provided to power and control the fan motor 5, suchareas of the cover 4 can conveniently house such other devices andconnect to wiring without other ceiling openings, separate junctionboxes and visual disturbance of the ceiling or wall.

Although the above description relates to a specific preferredembodiment as presently contemplated by the inventor, it will beunderstood that the invention in its broad aspect includes mechanicaland functional equivalents of the elements described herein.

1. A recessed fan inlet cover, for covering an enclosure inlet openingof an exhaust fan enclosure to provide an air flow channel into the fanenclosure while impeding sound emission from the fan enclosure, the faninlet cover comprising: a cover frame having an outer peripheral edgeextending outward of the enclosure inlet opening and having an inneredge defining a substantially planar frame surface, the frame having anupwardly recessed mounting surface joined to the inner edge with anarcuate wall, the mounting surface having an intake opening; and a coverplug mounted to the recessed mounting surface downwardly spaced from themounting surface, the plug having a substantially planar plug surfaceco-planar with said frame surface, the plug having an outer peripheraledge with an inwardly projecting lip, the plug having a sound absorbinglayer on an upper surface opposite said planar plug surface; wherein anair flow channel is defined between said arcuate wall and said lip. 2.The recessed fan inlet cover of claim 1 wherein the air flow channel hasan intake area relative to an enclosure inlet opening area is in therange of 40-60 percent.
 3. The recessed fan inlet cover of claim 2wherein the air flow channel has an intake area relative to an enclosureinlet opening area is in the range of 45-55 percent.
 4. The recessed faninlet cover of claim 1 including a sloping planar wall extendingupwardly and inwardly from the the inner edge to the arcuate wall.